Low risk deployment passenger airbag system using slim type passenger airbag module

ABSTRACT

Disclosed herein is a low risk deployment passenger airbag system using a slim type passenger airbag module which is minimized in height and/or length, such that a top airbag and a mid airbag can be installed in a limited space defined by an instrument panel. In the slim type passenger airbag module used in the low risk deployment passenger airbag system, a disk type inflator is used, unlike the conventional art using a cylindrical inflator, an upper end of the disk inflator is disposed in an airbag housing, and a retainer for supporting the cushion is brought into close contact with the bottom (or the rear surface) of the airbag housing in which the disk type inflator is provided, thus minimizing the height and/or length of the passenger airbag module. Thereby, the slim type passenger airbag module is suitable for the low risk deployment passenger airbag system. Furthermore, in the low risk deployment passenger airbag system, to deploy the cushions of the top and mid airbags substantially horizontally towards a passenger seat when a vehicle accident occurs, the distance between the top airbag and the mid airbag is within a range from 100 mm to 250 mm, the top airbag is inclined at an angle ranging from 60° to 75° with respect to the horizontal surface, and the mid airbag is inclined at 15° or less with respect to the horizontal surface.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to passenger airbag modulesmounted to instrument panels of vehicles and low risk deploymentpassenger airbag systems having top airbags and mid airbags which arerespectively mounted to upper surfaces and front surfaces of instrumentpanels and, more particularly, to a low risk deployment passenger airbagsystem using a slim type passenger airbag module which is minimized inheight and/or length, such that two passenger airbag modules, that is, atop airbag and a mid airbag, can be installed in a limited space definedby an instrument panel.

2. Description of the Related Art

Generally, airbag modules are installed in vehicles to protect driversand passengers from major impact when a vehicle crash occurs. Theairbags are classified into a driver airbag (DAB), which is installed ina steering handle of a driver's seat, and a passenger airbag (PAB),which is installed in an instrument panel across from a passenger seat,depending on the installation position thereof.

Particularly, the present invention relates to passenger airbags. Thepassenger airbags are classified into a top airbag, which is mounted tothe horizontal upper surface of the instrument panel, and a mid airbag,which is mounted to a vertical surface of the instrument panel above aglove box, depending on an installation position thereof.

As shown in FIGS. 1 a and 1 b, a conventional passenger airbag systemincludes a single passenger airbag module, which is provided inside anupper or front surface of an instrument panel. As an example, FIG. 1 ashows a conventional airbag system which includes a single top airbagmodule provided inside the upper surface of the instrument panel. FIG. 1b shows a conventional airbag system which includes a single mid airbagmodule provided inside the front surface of the instrument panel.

However, the conventional passenger airbag system having the single topor mid airbag is problematic in that, when a vehicle accident occurs, acushion inflated towards a passenger seat strikes the head of anout-of-position occupant (OOP), such as a child or a small adult, thusresulting in a severe injury to his/her neck. In detail, in the case ofFIG. 1 a, when a vehicle accident occurs, as designated by the dottedlines, while the cushion 5 of the top airbag is deployed, a componentforce 6 that is deployed downwards is generated. The downward deploymentcomponent force 6 strikes the head of a child 1, who is adjacent to theinstrument panel, in a downward direction, thus resulting in a severeinjury to the neck of the child 1. In the case of FIG. 1 b, while theairbag is deployed, a mid airbag cushion 9 generates a component force10 that is deployed upwards. The upward deployment component force 10strikes the jaw of an out-of-position child 1 in an upward direction,thus resulting in a severe injury to the neck of the child.

In an effort to overcome the above problems, recently, a low riskdeployment passenger airbag system, in which two airbags arerespectively mounted to the upper and front surfaces of the instrumentpanel, was developed. The low risk deployment passenger airbag systemincludes two airbag modules, that is, a top airbag module and a midairbag module, which have small volumes and are respectively mounted tothe upper surface and the front surface of the instrument panel. Thus,when the airbag is deployed, that is, when the top airbag and the midairbag are deployed, they are operated in conjunction with each other,so that they are substantially horizontally deployed towards the headand the chest of the occupant, thus preventing the downward or upwarddeployment component force 6 or 10 resulting in an injury to the neck ofthe out-of-position child.

FIG. 2 shows a preferred embodiment of “LOW RISK DEPLOYMENT PASSENGERAIRBAG SYSTEM” proposed in PCT international publication No. WO2005/120905, which was filed by the inventor of the present invention.

As shown in the drawing, the conventional low risk deployment passengerairbag system includes a top airbag, which is mounted to the uppersurface of an instrument panel, and a mid airbag, which is mounted tothe front surface of the instrument panel. In the conventional low riskdeployment passenger airbag system having the above-mentionedconstruction, when a vehicle accident occurs, while the airbags areoperated, a top airbag cushion 14 and a mid airbag cushion 16 comes intocontact with each other and are operated in conjunction with each other,so that they are substantially horizontally deployed towards the headand the chest of an adult occupant 2 who is seated on a passenger seat(refer to the arrows designated by the reference numerals 17 and 18).Therefore, the neck of an out-of-position child or small adult 1 isprevented from being injured by the deployment of the airbag.

The present invention provides a slim type passenger airbag module forsuch low risk deployment passenger airbag systems. That is, in such alow risk deployment passenger airbag system, because the top airbagmodule and the mid airbag module must be mounted to the rear surface ofthe instrument panel in a limited space defined by the instrument panel,the installation area and space are insufficient. Therefore, in order toinstall two passenger airbag modules in the limited space of theinstrument panel, a slim type passenger airbag module having a lowheight, that is, a small size, is required.

Furthermore, the present invention relates to an installationrelationship between the top airbag and the mid airbag provided in thelow risk deployment passenger airbag system, that is, it relates to thedistance and angle between the two passenger airbag modules. In detail,the low risk deployment passenger airbag system must be constructed suchthat, when the airbag system is operated, the cushions of the top airbagand the mid airbag are horizontally deployed by contact, that is,interference therebetween. For this, the distance and angle between thetop airbag and the mid airbag must be defined within appropriate ranges.Therefore, a slim type passenger airbag module that meets the aboverequirements is necessary.

FIGS. 3 a and 3 b are a perspective view and a sectional view showing anexample of a conventional passenger airbag module. As shown in thedrawings, the conventional passenger airbag module 100 includes abox-shaped airbag housing 20, a cylindrical inflator 31, whichdischarges deployment gas, a cushion 40, which is inflated towards apassenger seat using deployment gas, and a retainer 50, which supportsthe cushion 40.

In detail, the airbag housing 20 includes a cushion housing 21 and aninflator housing 22. The cushion 40, which is folded into apredetermined shape, is received in the cushion housing 21. Thecylindrical inflator 31 is installed in the inflator housing 22. Here,the cushion housing 21 has an opening 25, through which the cushion 40is inflated and is deployed by deployment gas towards the passengerseat, and a mounting flange 27, which has bolt holes and is integrallyprovided around the rim of the opening 25.

The inflator housing 22 has a cylindrical shape and is open at an upperend thereof. Coupling holes are formed through opposite ends of theinflator housing 22, so that the opposite ends of the cylindricalinflator 31 are inserted into and fastened to the coupling holes in theinflator housing 22. Furthermore, a bracket 64, which fastens thepassenger airbag module to a tie bar 63, is mounted to the outer surfaceof the lower end of the inflator housing 22.

The cylindrical inflator 31 has a can structure. A gas discharge hole,through which deployment gas is discharged when a vehicle accidentoccurs, is formed at a predetermined position through the inflator 30.Furthermore, a bolt 32 is provided on one end of the cylindricalinflator 31, so that the cylindrical inflator 31 can be fastened to theend of the inflator housing 22 by tightening the bolt 32 into a nut 34.A connector 38 for electrical connection of the cylindrical inflator 31is coupled to the other end of the cylindrical inflator 31.

The retainer 50 is fixed between the cushion housing 21 and the inflatorhousing 22, and fastens an inlet part of the cushion 40 to the cushionhousing 21. In addition, a plurality of passing holes 51, through whichdeployment gas passes, and a plurality of bolt holes for the retainer 50to the cushion housing 21 are formed through the retainer 50. The inletpart of the cushion 40 is fastened to the retainer 50 by coupling bolts.

Meanwhile, FIG. 4 is a schematic sectional view showing an instrumentpanel, to which a top airbag and a mid airbag are mounted. As shown inthe drawing, the top airbag T is mounted to the upper surface of theinstrument panel 65, and the mid airbag M is mounted to the frontsurface of the instrument panel 65. As such, the two passenger airbagmodules T and M are installed in a limited installation area A, which isdefined inside the rear surface of the instrument panel.

That is, the top airbag module T cannot be disposed in an area from ajunction between a windshield glass G and the instrument panel 65 to aposition spaced apart from the junction by a predetermined distance (L),in order to provide space for the rotation of an airbag door.Furthermore, because a glove box (GB) must be installed inside the frontpanel of the instrument panel 65, the mid airbag module M cannot beinstalled in that area. In addition, the top airbag module T and the midairbag module M must be coupled to the tie bar 63, the passenger airbagmodules T and M cannot be disposed below the tie bar 63. Therefore, thearea for installation of the two passenger airbag modules T and M islimited to the shaded area A, which is defined in the dotted line.Furthermore, recently, vehicles, in which a concave depression is formedin the upper surface of the instrument panel or the front surface of theinstrument panel is curved, are increasing in number. Thus, the area Afor installation of the two passenger airbag modules T and M is furtherreduced.

Therefore, a slim type passenger airbag module, which makes it possibleto install two airbag modules in the limited installation area A insidethe instrument panel, is required. Furthermore, the slim type passengerairbag module, which can be applied to even the curved surface of theinstrument panel, is required. In addition, the slim type passengerairbag module, which can meet requirements, such as the distance (D)between the top airbag T and the mid airbag M and inclination angles (a)and (0) thereof, such that the cushions of the top airbag T and the midairbag M can be horizontally deployed by operating in conjunction witheach other, is required.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and an object of the presentinvention is to provide a low risk passenger airbag system whichincludes at least one slim type passenger airbag module having minimalheight and/or length such that, when the airbag is operated, cushions ofa top airbag and a mid airbag, which are respectively mounted to theupper and front surfaces of an instrument panel, can be substantiallyhorizontally deployed in conjunction with each other.

Another object of the present invention is to provide a low riskpassenger airbag system in which at least one of the top airbag and themid airbag, which are installed in a limited space defined inside therear surface of the instrument panel, comprises a slim type passengerairbag module having minimal height and/or length such that the distancebetween the top airbag and the mid airbag can be within a predeterminedrange, and the inclination angles of the top airbag and the mid airbagwith respect to the horizontal surface can be within predeterminedranges.

Another object of the present invention is to provide a low riskpassenger airbag system in which at least one of the top airbag and themid airbag, which are respectively mounted to the upper surface and thefront surface of the instrument panel, comprises a slim type passengerairbag module having minimal height and/or length, such that it can meetthe low risk deployment criteria for passenger airbags set by theNational Highway Traffic Safety Administration (NHTSA).

In order to accomplish the above object, in a first aspect of a slimtype passenger airbag module used in the low risk deployment passengerairbag system, a disk type inflator is used, unlike the conventionalart, which uses a cylindrical inflator, and an upper end of the diskinflator is disposed in an airbag housing. Furthermore, a retainer forsupporting the cushion is brought into close contact with the bottom ofthe airbag housing and integrally fastens the cushion and the disk typeinflator to the airbag housing, thus reducing the height and/or lengthof the passenger airbag module.

In a second aspect of a slim type passenger airbag module used in thelow risk deployment passenger airbag system, the opening in the airbaghousing, through which the cushion is deployed, and the upper surface ofthe disk type inflator, which supplies deployment gas into the cushion,are perpendicular to each other, so that the height of the opening canbe determined independent of the size of the disk type inflator, thusreducing the height or length of the passenger airbag module.

In a preferred embodiment of the low risk deployment passenger airbagsystem according to the present invention having passenger airbagmodules respectively mounted to the upper surface and the front surfaceof an instrument panel, at least one of the passenger airbag modulescomprises a slim type passenger airbag module, comprising: a box-shapedairbag housing, having an opening in a front end thereof, and a flangeprovided around the opening of the box-shaped airbag housing, a disktype inflator, an upper end of which is inserted into the airbag housingthrough a circular insert hole formed through a rear surface of theairbag housing, which is opposite the opening, a cushion stored in theairbag housing in a folded state such that the cushion is deployedtowards a passenger seat through the opening by deployment gasdischarged from the disk type inflator; and a retainer fastening both aninlet part of the cushion and a ring-shaped flange, provided around thecircumferential outer surface of the disk type inflator, to the rearsurface of the airbag housing using a locking bolt, the retainer havinga circular through hole through which the upper end of the disk typeinflator passes.

In another embodiment of the low risk deployment passenger airbag systemhaving passenger airbag modules respectively mounted to an upper surfaceand a front surface of an instrument panel, at least one of thepassenger airbag modules comprises a slim type passenger airbag module,comprising- a box-shaped airbag housing, having an opening in a frontend thereof, and a flange provided around the opening of the box-shapedairbag housing, a disk type inflator, an upper end of which is insertedinto the airbag housing through a circular insert hole formed through abottom of the airbag housing, which is perpendicular to the opening, acushion stored in the airbag housing in a folded state such that thecushion is deployed towards a passenger seat through the opening bydeployment gas discharged from the disk type inflator; and a retainerfastening both an inlet part of the cushion and a ring-shaped flange,provided around a circumferential outer surface of the disk typeinflator, to the bottom of the airbag housing using a locking bolt, theretainer having a circular through hole, through which the upper end ofthe disk type inflator passes.

In the low risk deployment passenger airbag system of the presentinvention, a distance between centers of the two passenger airbagmodules, which are respectively mounted to the upper surface and thefront surface of the instrument panel, may be within a range from 100 mmto 250 mm, such that, when a vehicle crash occurs, two cushions of thepassenger airbag modules are horizontally deployed towards the passengerseat in conjunction with each other.

Furthermore, in the low risk deployment passenger airbag system of thepresent invention, the airbag module, which is mounted to the uppersurface of the instrument panel, may be inclined at an angle rangingfrom 60° to 75° with respect to a horizontal surface, and the airbagmodule, which is mounted to the front surface of the instrument panel,may be parallel to the horizontal surface or be inclined at an angleranging from 0° to 15° with respect to the horizontal surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIGS. 1 a and 1 b are side views showing conventional passenger airbagsystems;

FIG. 2 is a side view showing a conventional low risk deploymentpassenger airbag system;

FIGS. 3 a and 3 b respectively are a perspective view and a sectionalview showing an example of a passenger airbag module according to aconventional technique;

FIG. 4 is a schematic sectional view of an instrument panel illustratingan area for installing a top airbag and a mid airbag according to theconventional technique;

FIGS. 5 a, 5 b and 5 c are a perspective view, an exploded perspectiveview and a sectional view showing a slim type passenger airbag moduleused in a low risk deployment passenger airbag system, according to afirst embodiment of the present invention;

FIGS. 6 a and 6 b are a perspective and a sectional view showing a slimtype passenger airbag module, according to a second embodiment of thepresent invention;

FIGS. 7 a and 7 b are a perspective and an exploded perspective viewshowing a slim type passenger airbag module, according to a thirdembodiment of the present invention;

FIGS. 8 a and 8 b are a perspective and a sectional view showing a slimtype passenger airbag module, according to a fourth embodiment of thepresent invention;

FIGS. 9 a and 9 b are a perspective and a sectional view showing a slimtype passenger airbag module, according to a fifth embodiment of thepresent invention;

FIG. 10 is a view illustrating the method of folding an airbag cushionused in the slim type passenger airbag module according to the presentinvention; and

FIGS. 11 a-11 e are schematic views showing the low risk deploymentpassenger airbag systems using the slim type airbag modules according tothe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of a low risk deployment airbagsystem using a slim type airbag module according to the presentinvention will be described in detail with reference to the attacheddrawings.

FIGS. 5 a, 5 b and 5 c are a perspective view, an exploded perspectiveview and a sectional view showing a slim type passenger airbag module101 used in a low risk deployment passenger airbag system, according toa first embodiment of the present invention.

As shown in the drawings, the slim type passenger airbag module 101includes a box-shaped airbag housing 20, which has an opening 25 in anupper end thereof, and a disk type inflator 30, which is mounted to thebottom 23 of the airbag housing 20 and discharges deployment gas. Theslim type passenger airbag module 101 further includes a cushion 40 tobe inflated through the opening 25 towards a passenger seat bydeployment gas discharged from the disk type inflator 30, and a retainer50, which fastens an inlet part 41 (see, FIG. 5 b) of the cushion 40 andthe disk type inflator 30 to the bottom 23 of the airbag housing 20.

In detail, the box-shaped airbag housing 20 is made of plastic or metaland has in the upper end thereof the opening 25, through which thecushion 40 inflated by the deployment gas is deployed towards thepassenger seat. Furthermore, a mounting flange 27, in which bolt holes26 are formed, is integrally provided around the rim of the opening 25.The mounting flange 27 is brought into close contact with and isfastened to the rear surface of an instrument panel 65. A circularinsert hole 24 for installation of the disk type inflator 30 is formedthrough the bottom 23 of the airbag housing 20 which is opposite theopening 25.

The inflator 30 has a disk-shaped can structure. The upper half of theinflator 30 is inserted into the airbag housing 20 through the circularinsert hole 24. Furthermore, a ring-shaped flange 33, which is broughtinto contact with the rear surface of the bottom 23 of the airbaghousing 20, is provided around the circumferential outer surface of theinflator 30. Bolt holes 35, which correspond to bolt holes formedthrough the bottom 23 of the airbag housing 20, are formed through thering-shaped flange 33. A gas discharge hole (not shown), through whichdeployment gas is discharged, is formed in the upper surface of theinflator 30, which is disposed in the airbag housing 20. A connector(not shown), which connects to an outside sensor, is provided in thelower surface of the inflator 30 which is disposed outside the airbaghousing 20.

The retainer 50 is a plate which is placed in the airbag housing 20 tosupport the cushion 40. A through hole 53, through which the upper halfof the inflator 30 passes, is formed at a central position through theretainer 50. Several locking bolts 55, which pass through bolt holes 45formed in the inlet part 41 of the cushion 40, the bolt holes 35 of thering-shaped flange 33 of the inflator 30, and the bolt holes 29 of thebottom 23 of the airbag housing 20, are provided under the lower surfaceof the retainer 50 around the through hole 53.

Therefore, while the upper half of the inflator 30 is inserted into thereceiving space in the airbag housing 20 through the circular inserthole 24, the locking bolts 55 of the retainer 50 are inserted into thebolt holes 45, formed in the inlet part 41 of the cushion 40, the boltholes 29 of the bottom 23 of the airbag housing 20, and the bolt holes35 of the flange 33 of the inflator 30, and, thereafter, are tightenedinto respective locking nuts 56. Thereby, the inlet part 41 of thecushion 40 and the flange 33 of the inflator 30 are reliably fastened tothe bottom 23 of the airbag housing 20. Meanwhile, the cushion 40 isfolded in one manner selected from among a zigzag 1-tug manner, a zigzagroll manner and a zigzag manner, and is placed in the airbag housing 20.For example, FIG. 10 illustrates a preferred embodiment of the cushion40 used in the slim type passenger airbag module according to thepresent invention and, more particularly, illustrates a process offolding the cushion 40 in the zigzag 1-tug manner.

As shown in FIG. 5 c, in the slim type passenger airbag module 101according to the first embodiment of the present invention, the mountingflange 27 of the airbag housing 20 is brought into contact with the rearsurface of the instrument panel 65 such that locking bolts 66 providedunder the rear surface of the instrument panel 65 are inserted throughthe respective bolt holes 26 formed in the mounting flange 27, and,thereafter, the locking bolts 66 are tightened into respective lockingnuts 67. Furthermore, a bracket (not shown) mounted to the bottom of theairbag housing 20 is fastened to a tie bar (not shown) using couplingmeans such as nuts and bolts. Meanwhile, a separate housing airbag door(not shown) may be provided in the airbag housing 20. Preferably, anairbag door 69 is integrally provided in the instrument panel 65 withouta separate housing airbag door, and a breaking groove 68 is formed inthe rear surface of the instrument panel 65 in a shape corresponding tothe airbag door 69. Thus, when the vehicle accident occurs, the breakinggroove 68 is broken by the expansion force of the cushion 40, and theairbag door 69 is simultaneously opened.

As such, in the slim type passenger airbag module 101 according to thefirst embodiment of the present invention, the airbag housing 20 isconstructed into a single body without being divided into a cushionhousing and an inflator housing. Furthermore, unlike the conventionalart, which uses a cylindrical inflator, a disk type inflator 30 is used,and the upper half of the disk type inflator 30 is disposed in theairbag housing 20 while the lower half thereof is disposed outside theairbag housing 20. In addition, the retainer 50 is brought into closecontact with and is mounted to the bottom 23 of the airbag housing 20,such that the inlet part 41 of the cushion 40 and the flange 33 of thedisk type inflator 30 are fastened together to the bottom 23 of theairbag housing 20 by the retainer 50. Therefore, the assembly structureis simplified, and the length of the slim type passenger airbag module101 is minimized.

Next, a slim type passenger airbag module 102 used in a low riskdeployment passenger airbag system according to a second embodiment ofthe present invention will be described herein below with reference tothe attached drawings.

FIGS. 6 a and 6 b are a perspective view and a sectional view showingthe slim type passenger airbag module 102 used in the low riskdeployment passenger airbag system, according to the second embodimentof the present invention. As shown in the drawings, the slim typepassenger airbag module 102 according to the second embodiment of thepresent invention includes a box-shaped airbag housing 20, which has anopening 25 in a front end thereof, and a disk type inflator 30, which ismounted to the bottom 23 of the airbag housing 20 and dischargesdeployment gas. The slim type passenger airbag module 102 furtherincludes a cushion 40 which is inflated through the opening 25 towards apassenger seat by deployment gas discharged from the disk type inflator30, and a retainer 50, which fastens an inlet part 41 (see, FIG. 6 b) ofthe cushion 40 and the disk type inflator 30 to the bottom 23 of theairbag housing 20. That is, the slim type passenger airbag module 102according to the second embodiment is constructed such that the opening25 formed in the front end of the airbag housing 20 is perpendicular tothe upper surface of the disk type inflator 30 provided through thebottom 23 of the airbag housing 20, thus minimizing the height of theslim type passenger airbag module 102.

In detail, the box-shaped airbag housing 20 is made of plastic or metal,and has in the front end thereof the opening 25, through which thecushion 40 inflated by the deployment gas is deployed towards thepassenger seat. Furthermore, a mounting flange 27, in which bolt holes26 are formed, is integrally provided around the rim of the opening 25.The mounting flange 27 is brought into close contact with and isfastened to the rear surface of an instrument panel 65. A circularinsert hole 24 for installation of the disk type inflator 30 is formedthrough the bottom 23 of the airbag housing 20.

The inflator 30 has a disk-shaped can structure. The upper half of theinflator 30 is inserted into the airbag housing 20 through the circularinsert hole 24. A ring-shaped flange 33, which is brought into contactwith the bottom 23 of the airbag housing 20, is provided around thecircumferential outer surface of the inflator 30. Bolt holes 35, whichcorrespond to bolt holes formed through the bottom 23 of the airbaghousing 20, are formed through the ring-shaped flange 33.

The retainer 50 is a plate which is placed in the airbag housing 20 andsupports the cushion 40. A through hole 53, through which the upper halfof the inflator 30 passes, is formed at a central position through theretainer 50. Several locking bolts 55, which pass through bolt holes 45formed in the inlet part 41 of the cushion 40 and the bolt holes 35 ofthe ring-shaped flange 33 of the inflator 30, are provided in theretainer 50 around the through hole 53.

Therefore, as shown in FIG. 6 b, in the state in which the upper half ofthe inflator 30 is inserted into the receiving space in the airbaghousing 20 through the circular insert hole 24, the locking bolts 55 ofthe retainer 50 are inserted into the bolt holes 45 of the inlet part 41of the cushion 40, the bolt holes 29 of the bottom 23 of the airbaghousing 20, and the bolt holes 35 of the flange 33 of the inflator 30,and, thereafter, are tightened into respective locking nuts 56. Thereby,the inlet part 41 of the cushion 40 and the flange 33 of the inflator 30are reliably fastened to the bottom 23 of the airbag housing 20.

As such, in the slim type airbag module 102 according to the secondembodiment, the opening 25 is formed in the front end of the airbaghousing 20, and the disk type inflator 30 is mounted to the bottom 23 ofthe airbag housing 20 such that it is perpendicular to the opening 25.Therefore, the height of the slim type airbag module 102 can beminimized independently of the size of the disk type inflator 30.

Hereinafter, a slim type passenger airbag module 103 according to athird embodiment of the present invention will be described herein belowwith reference to FIGS. 7 a and 7 b. FIG. 7 a is a perspective view ofthe slim type passenger airbag module 103 according to the thirdembodiment, and FIG. 7 b is an exploded perspective view of the slimtype passenger airbag module 103.

As shown in the drawings, an inflator 30, a cushion 40 and a retainer 40of the slim type passenger airbag module 103 according to the thirdembodiment of the present invention are the same as those of the slimtype passenger airbag module 102 according to the second embodiment, butthe front part of the airbag housing 20, in which the opening 25 isformed, that is, a cushion receiving part 71, is higher than in the slimtype passenger airbag module 102 according to the second embodiment,such that a cushion 40 having a larger volume can be placed therein. Assuch, in the slim type passenger airbag module 103 according to thethird embodiment, the rear part of the airbag housing 20, that is, aninflator receiving part 72, has a height different from that of thecushion receiving part 71, so that a stepped part 73 having apredetermined height is formed therebetween.

In detail, the slim type passenger airbag module 103 according to thethird embodiment includes the box-shaped airbag housing 20, which has anopening 25 in a front end thereof and has the stepped part 73 at anintermediate position thereof so that the cushion receiving part 71, inwhich the cushion 40 is placed, is higher than the other part of theairbag housing 20. The slim type passenger airbag module 103 furtherincludes the disk type inflator 30, which is mounted to the uppersurface 23 of the inflator receiving part 74 of the airbag housing 20and discharges deployment gas, the cushion 40 to be inflated through theopening 25 towards a passenger seat by deployment gas discharged fromthe disk type inflator 30, and the retainer 50, which fastens the inletpart 41 (see, FIG. 7 b) of the cushion 40 and a ring-shaped flange 33 ofthe disk type inflator 30 to the upper surface 74 of the inflatorreceiving part 72 of the airbag housing 20. The general construction ofthe slim type passenger airbag module 103, other than the abovestructure, remains the same as the above-mentioned embodiments,therefore further explanation is deemed unnecessary.

As such, the slim type passenger airbag module 103 according to thethird embodiment is constructed such that the cushion receiving part 71is higher than the inflator receiving part 72 and thus can receive acushion 40 having a larger volume therein but maintains the height ofthe rear part of the airbag housing 20 at a minimum, thus ensuringsufficient space for installation of two passenger airbag modules in asingle instrument panel 65.

FIGS. 8 a and 8 b are a perspective view and a sectional view showing aslim type passenger airbag module 104, according to a fourth embodimentof the present invention.

As shown in the drawings, the slim type passenger airbag module 104according to the fourth embodiment of the present invention includes abox-shaped airbag housing 20, which has an opening 25 in a front endthereof and has an inclined surface 77, which is inclined at apredetermined angle, on the surface opposite the opening 25. The slimtype passenger airbag module 104 further includes a disk type inflator30, which is mounted to the inclined surface 77 of the airbag housing 20and discharges deployment gas, a cushion 40 to be inflated through theopening 25 towards a passenger seat by deployment gas discharged fromthe disk type inflator 30, and a retainer 50, which fastens an inletpart 41 (see, FIG. 6 b) of the cushion 40 and the disk type inflator 30to the inclined surface 77 of the airbag housing 20.

In detail, the box-shaped airbag housing 20 is made of plastic or metaland has in the front end thereof the opening 25, through which thecushion 40 inflated by the deployment gas is deployed towards thepassenger seat. The inclined surface 77 is formed opposite the opening25. Furthermore, a mounting flange 27, in which bolt holes 26 areformed, is integrally provided around the rim of the opening 25. Themounting flange 27 is fastened to the rear surface of an instrumentpanel 65, thus mounting the slim type passenger airbag module to theinstrument panel 65. A circular insert hole 24 for installation the disktype inflator 30 is formed through the inclined surface 77 of the airbaghousing 20 which is opposite the opening 25.

The inflator 30 has a disk-shaped can structure. The upper half of theinflator 30 is inserted into the airbag housing 20 through the circularinsert hole 24. A ring-shaped flange 33, which is brought into contactwith the inclined surface 77 of the airbag housing 20, is providedaround the circumferential outer surface of the inflator 30. Bolt holes35, which correspond to bolt holes formed through the inclined surface77 of the airbag housing 20, are formed through the ring-shaped flange33. The general construction of the slim type passenger airbag module104, other than the structures noted above, remains the same as theprevious embodiment, therefore further explanation is deemedunnecessary.

FIGS. 9 a and 9 b are a perspective view and a sectional view showing aslim type passenger airbag module 105, according to a fifth embodimentof the present invention.

As shown in the drawings, the slim type passenger airbag module 105according to the fifth embodiment of the present invention includes abox-shaped airbag housing 20, which has therein an opening 25 formed atan incline, and a disk type inflator 30, which is mounted to a rearsurface 79 of the airbag housing 20 and discharges deployment gas. Theslim type passenger airbag module 105 further includes a cushion 40 thatis inflated through the opening 25 towards a passenger seat bydeployment gas discharged from the disk type inflator 30, and a retainer50, which fastens an inlet part 41 (see, FIG. 6 b) of the cushion 40 andthe disk type inflator 30 to the rear surface 79 of the airbag housing20.

In this embodiment, the box-shaped airbag housing 20 is made of plasticor metal and has in the front end thereof the opening 25, which isinclined at a predetermined angle, and through which the cushion 40inflated by the deployment gas is deployed. Furthermore, a mountingflange 27, in which bolt holes 26 are formed, is integrally providedaround the rim of the opening 25. Here, the inclination angle of theopening 25 corresponds to the curvature of an instrument panel 65. Acircular insert hole 24 for installation of the disk type inflator 30 isformed through the rear surface 97 of the airbag housing 20. The generalconstruction of the slim type passenger airbag module 105 other than thestructures noted above remains the same as the previous embodiment. Theslim type passenger airbag module 105 according to the fifth embodimentcan be appropriately applied to an instrument panel 65 which is inclinedat a predetermined angle and has a curved surface. In addition, the slimtype passenger airbag module 101, 102, 103, 104 of each embodiment ofthe present invention can also have the same effect by forming thesurface defining the opening 25 at an incline or in a curved shape.

As described above, the slim type passenger airbag module of the presentinvention has the disk type inflator, unlike the conventional art havingthe cylindrical inflator, and is constructed such that the inflator andthe opening face each other, are perpendicular to each other, or areangled with respect to each other in order to minimize the height and/orlength of the airbag module, and such that the height of the rear partof the airbag housing is relatively low, thus ensuring sufficient spaceto install two passenger airbag modules to the rear surface of, orunderneath, a single instrument panel.

Hereinafter, a preferred embodiment of a low risk deployment passengerairbag system using a slim type passenger airbag module according to thepresent invention will be described in detail with reference to theattached drawings.

As shown in FIG. 2, in the low risk deployment passenger airbag systemof the present invention, when a vehicle crash occurs, because thecushion of a top airbag T and the cushion of a mid airbag M arehorizontally deployed towards a passenger seat in conjunction with eachother, an impact applied by airbag inflation to an out-of positionoccupant, for example, a child, can be reduced.

Therefore, to achieve the intended function of the low risk deploymentpassenger airbag system, as shown in FIG. 4, the distance (D) betweenthe centers of the top airbag T and the mid airbag M must beappropriately set. In detail, the distance (D) between the centers ofthe top airbag T and the mid airbag M must be defined within anappropriate range such that two deploying cushions graze and contacteach other. If the distance (D) between the centers of the top airbag Tand the mid airbag M is excessively great, the two cushions cannot beoperated in conjunction with each other. Conversely, if the distance (D)therebetween is excessively short, because the two cushions stronglybump against each other and rebound away from each other, they cannot behorizontally deployed.

Furthermore, the top airbag T and the mid airbag M must be installedsuch that they are angled towards each other within a predeterminedangular range. If the angle between the top airbag T and the mid airbagM is too large, the two cushions cannot contact each other when beingdeployed. Conversely, if the angle between the top airbag T and the midairbag M is too small, because the two cushions strongly bump againsteach other and rebound away from each other, they cannot be horizontallydeployed.

Meanwhile, in the low risk deployment passenger airbag system, thevolume of the cushion of the top airbag T is greater than that of thecushion of the mid airbag M. The reason for this is that the top airbagT is disposed at a position relatively far from the occupant.Preferably, the ratio of the volume of the cushion of the top airbag Tto the cushion of the mid airbag M is 2:1. In the preferred embodimentof the low risk deployment passenger airbag system according to thepresent invention, the cushion of the top airbag T has a volume rangingfrom 60 L to 120 L, and the cushion of the mid airbag M has a volumeranging from 30 L to 70 L. Under the above conditions, it is preferablethat the distance (D) between the centers of the top airbag T and themid airbag M be within a range from 100 mm to 250 mm.

Furthermore, the inclination angle (θ) of the top airbag T with respectto a horizontal surface ranges from 60° to 75°, and an inclination angle(α) of the mid airbag M with respect to the horizontal surface rangesfrom 0° to 15°. That is, it is preferable that the angle between the topairbag T and the mid airbag M be approximately 60°.

Meanwhile, preferably, the operating pressure of the inflator used inthe top airbag T ranges from 200 kpa to 260 kpa in the case where thevolume thereof is 60 L, and the operating pressure of an inflator usedin the mid airbag M ranges from 100 kpa to 130 kpa in the case where thevolume thereof is 60 L.

Hereinafter, various embodiments of a low risk deployment passengerairbag system using a slim type passenger airbag module will beexplained with reference to FIGS. 11 a through 11 e.

To satisfy the above-mentioned conditions, such as the limited space A,the distance (D) between the top airbag T and the mid airbag M and theinclination angles (α) and (θ), at least one of the top airbag moduleand the mid airbag module which are installed in the instrument panelmust use a slim type passenger airbag module.

FIG. 11 a shows the case where the slim type passenger airbag modules101 according to the first embodiment are used in both the top airbag Tand the mid airbag M. FIG. 11 b shows the case where the height of thefront surface of the instrument panel is relatively low, so that theslim type passenger airbag module 101 according to the first embodimentis used for the top airbag T, and the slim type passenger airbag module102 according to the second embodiment is used for the mid airbag M.FIG. 11 c shows the case where the height of the front surface of theinstrument panel is sufficient but the distance between the mid airbag Mand the top airbag T is relatively short. In this case, the slim typepassenger airbag module 101 according to the first embodiment is used inthe top airbag T, and the slim type passenger airbag module 103according to the third embodiment is used in the mid airbag M. That is,in the case of the slim type passenger airbag module 103 according tothe third embodiment, because the height of the rear part is relativelylow, space for installation of the top airbag T is ensured.

FIG. 11 d shows the case where the front surface of the instrument panelis curved, and thus the slim type passenger airbag module 105 accordingto the fifth embodiment is used. In the slim type passenger airbagmodule 105 according to the fifth embodiment, the surface defining theopening is inclined, thus facilitating the coupling of the airbag moduleto the curved surface of the instrument panel. FIG. 11 e shows the casewhere the distance between the mid airbag M and the top airbag T isrelatively short and the height of the front surface of the instrumentpanel is relatively low. In this case, the slim type passenger airbagmodules 102 according to the second embodiment are used for both the topairbag T and the mid airbag M.

As such, the low risk deployment airbag system according to the presentinvention can be implemented using various combinations of the slim typepassenger airbag modules depending on conditions such as the limitedspace A, the distance (D) between the top airbag T and the mid airbag Mand the inclination angles (α) and (θ).

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, the scope of the present inventionis not limited to the above embodiments. Furthermore, those skilled inthe art will appreciate that various modifications, additions andsubstitutions are possible, without departing from the scope and spiritof the invention as disclosed in the accompanying claims. Therefore, thescope of the present invention must be defined by the accompanyingclaims.

As described above, the prevent invention provides various kinds of slimtype passenger airbag modules such that a top airbag module and a midairbag module can be installed in a limited space. Because the slim typepassenger airbag module of the present invention is relatively low inheight and relatively short in length and it can be manufactured intovarious types, the present invention makes it possible for two passengerairbags to be installed in a limited space.

In a low risk deployment passenger airbag system using the slim typepassenger airbag module according to the present invention, whencushions of a top airbag and a mid airbag, which are respectivelyprovided on an upper surface and a front surface of an instrument panel,are deployed in an accident, because the cushions are operated inconjunction with each other, they are deployed substantiallyhorizontally, thus preventing an out-of position child or a small adultfrom being injured by airbag inflation.

Therefore, the low risk deployment passenger airbag system using theslim type passenger airbag module according to the present invention canmeet the low risk deployment criteria for passenger airbags set by theNational Highway Traffic Safety Administration (NHTSA).

1. A low risk deployment passenger airbag system having passenger airbagmodules respectively mounted to an upper surface and a front surface ofan instrument panel, wherein at least one of the passenger airbagmodules comprises a slim type passenger airbag module, comprising: abox-shaped airbag housing, having an opening in a front end thereof, anda flange provided around the opening of the box-shaped airbag housing; adisk type inflator, an upper end of which is inserted into the airbaghousing through a circular insert hole formed through a rear surface ofthe airbag housing, which is opposite the opening; a cushion stored inthe airbag housing in a folded state such that the cushion is deployedtowards a passenger seat through the opening by deployment gasdischarged from the disk type inflator; and a retainer fastening both aninlet part of the cushion and a ring-shaped flange, provided around acircumferential outer surface of the disk type inflator, to the rearsurface of the airbag housing using a locking bolt, the retainer havinga circular through hole through which the upper end of the disk typeinflator passes.
 2. The low risk deployment passenger airbag systemusing the slim type passenger airbag module as set forth in claim 1,wherein the rear surface of the airbag housing, which is opposite theopening, comprises an inclined surface angled at a predetermined anglewith respect to the opening.
 3. The low risk deployment passenger airbagsystem using the slim type passenger airbag module as set forth in claim1, wherein the front end of the airbag housing having the openingcomprises an inclined surface angled at a predetermined angle.
 4. A lowrisk deployment passenger airbag system having passenger airbag modulesrespectively mounted to an upper surface and a front surface of aninstrument panel, wherein at least one of the passenger airbag modulescomprises a slim type passenger airbag module, comprising: a box-shapedairbag housing, having an opening in a front end thereof, and a flangeprovided around the opening of the box-shaped airbag housing; a disktype inflator, an upper end of which is inserted into the airbag housingthrough a circular insert hole formed through a bottom of the airbaghousing, which is perpendicular to the opening; a cushion stored in theairbag housing in a folded state such that the cushion is deployedtowards a passenger seat through the opening by deployment gasdischarged from the disk type inflator; and a retainer fastening both aninlet part of the cushion and a ring-shaped flange, provided around acircumferential outer surface of the disk type inflator, to the bottomof the airbag housing using a locking bolt, the retainer having acircular through hole, through which the upper end of the disk typeinflator passes.
 5. The low risk deployment passenger airbag systemusing the slim type passenger airbag module as set forth in claim 4,wherein a front part of the airbag housing, in which the opening isformed, is higher than a rear part of the airbag housing in which thedisk type inflator is provided, so that a stepped part having apredetermined height is defined between the front part and the rear partof the airbag housing.
 6. The low risk deployment passenger airbagsystem using the slim type passenger airbag module as set forth in claim1, wherein a distance between centers of the two passenger airbagmodules, which are respectively mounted to the upper surface and thefront surface of the instrument panel, is within a range from 100 mm to250 mm, such that, when a vehicle crash occurs, two cushions of thepassenger airbag modules are horizontally deployed towards the passengerseat in conjunction with each other.
 7. The low risk deploymentpassenger airbag system using the slim type passenger airbag module asset forth in claim 6, wherein the airbag module, which is mounted to theupper surface of the instrument panel, is inclined at an angle rangingfrom 60° to 75° with respect to a horizontal surface, and the airbagmodule, which is mounted to the front surface of the instrument panel,is parallel to the horizontal surface or is inclined at an angle rangingfrom 0° to 15° with respect to the horizontal surface.
 8. The low riskdeployment passenger airbag system using the slim type passenger airbagmodule as set forth in claim 6, wherein the cushion of the airbagmodule, which is mounted to the upper surface of the instrument panel,has a volume ranging from 60 L to 120 L, and the cushion of the airbagmodule, which is mounted to the front surface of the instrument panel,has a volume ranging from 30 L to 70 L.
 9. The low risk deploymentpassenger airbag system using the slim type passenger airbag module asset forth in claim 6, wherein an angle between the airbag module, whichis mounted to the upper surface of the instrument panel at an incline,and the airbag module, which is mounted to the front surface of theinstrument panel parallel thereto or at an incline, is 60°.
 10. The lowrisk deployment passenger airbag system using the slim type passengerairbag module as set forth in claim 2, wherein a distance betweencenters of the two passenger airbag modules, which are respectivelymounted to the upper surface and the front surface of the instrumentpanel, is within a range from 100 mm to 250 mm, such that, when avehicle crash occurs, two cushions of the passenger airbag modules arehorizontally deployed towards the passenger seat in conjunction witheach other.
 11. The low risk deployment passenger airbag system usingthe slim type passenger airbag module as set forth in claim 3, wherein adistance between centers of the two passenger airbag modules, which arerespectively mounted to the upper surface and the front surface of theinstrument panel, is within a range from 100 mm to 250 mm, such that,when a vehicle crash occurs, two cushions of the passenger airbagmodules are horizontally deployed towards the passenger seat inconjunction with each other.
 12. The low risk deployment passengerairbag system using the slim type passenger airbag module as set forthin claim 4, wherein a distance between centers of the two passengerairbag modules, which are respectively mounted to the upper surface andthe front surface of the instrument panel, is within a range from 100 mmto 250 mm, such that, when a vehicle crash occurs, two cushions of thepassenger airbag modules are horizontally deployed towards the passengerseat in conjunction with each other.
 13. The low risk deploymentpassenger airbag system using the slim type passenger airbag module asset forth in claim 5, wherein a distance between centers of the twopassenger airbag modules, which are respectively mounted to the uppersurface and the front surface of the instrument panel, is within a rangefrom 100 mm to 250 mm, such that, when a vehicle crash occurs, twocushions of the passenger airbag modules are horizontally deployedtowards the passenger seat in conjunction with each other.